In many instances, emergency lighting systems having battery-backup are environmentally limited in their operation by extreme temperatures, whether hot or cold. For instance, external fluorescent building-mount lighting units with battery packs generally cannot operate below approximately −40° Fahrenheit, which is a temperature experienced in many parts of the world. Furthermore, fluorescent light output is reduced in cold weather and incandescent lamps in HID fixtures require large, bulky battery packs because of their power needs. Because of the size of these large battery packs, they are generally remotely mounted and separately wired to the fixture. Further, many emergency fixtures required wired connections to two sources of power, a primary source and a secondary source. In the normal mode of operation, the primary source provides power to the fixture's lamp. The secondary source provides lighting power to the fixture's lamp when the primary source is in an outage mode. The secondary source can be, for example, a reliable circuit, a circuit from an uninterruptible power supply (UPS) or a centralized battery, etc. The secondary source provides lighting power to the fixture's lamp when the primary source is in an outage mode.
Therefore, what is needed is a lighting system that overcomes many of the challenges found in the art, some of which are described above.